System of electrical distribution.



No. 638,085. Patented Nov. 28; I899. L. ANDREWS.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Applicstion filed Apr. 4, 1898.)

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N0. 638,085. Patented Nov. 28, I899. L. ANDREWS.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Applicntion filed Apr. 4, 1898.)

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No. 638,085. Patented Nov. 28, I899. L. ANDREWS.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Apr. 4, 1898.) (No Model.)

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I v WW Alfarizey UNITED STATES LEONARD ANDREVS, O

F HASTINGS, ENGLAND.

SYSTEM OF ELECTRICAL DISTREBUTION.

SPECIFICATION forming part of Letters Patent No. 638,085, dated November28, 1899.

Application filed April 4, 1898. Serial No. 676,280. (No model.)

To LLZZ whom it may concern:

Be it known that I, LEONARD ANDREWS, a subject of the Queen of GreatBritain and Ireland, residing at Hastings, in the county of Sussex,England, have invented Improvements in or Relating to Systems ofElectrical Distribution, of which the followingis a specification.

In electrical distributing systems in which electrical energy isdistributed from a central station to substations or distributingpoints(hereinafter called substations) by means of feeders it has heretoforebeen common to provide the feeders with hand-operated switches and tointerconnect the substations by conductors, (hereinafter called, fordistinction, auxiliary feeders) so that any main feeder may betemporarily cut out for repair or other purpose without interrupting thesupply of electricity to the substation to which it is connected. lVherefeeders and substations are arranged in this manner, it is usual toinsert an excess-current cut-out, such as a safety-fuse or magnetic orother eX- cess-current cutout, at each end of each feeder-viz., where itleaves the generatingstation and where it is connected to thesubstationso that should a short circuit occur on any feeder the safetydevices at its extremities will immediately cut it out of circuit. Itnot unfrequentlyhappens, however, that the cut-outs in a healthy feederwill operate before the cut-out at the distributing end of the faultyfeeder, owing to the fact that the healthy feeder has to carrysufficient current to operate the faulty-feeders cut-out inaddition tothe useful work normally supplied by both feeders, with the result thatthe supply of electricity to the district fed by the two feeders will beinterfered with.

Now this invent-ion has for its object to obviate this greatdisadvantage. For this purpose I provide in connection with the outgoingand return feeders, nearto their points of connection with eachsubstation, automatic cut out apparatus so constructed and arranged thatit will carry as heavy a current as the feeders so long as the electricenergy is being supplied from the generating-station to thedistributing-station, but will cut out with a comparatively smallcurrent returning toward the generating-station, the construction of thecut-out apparatus, moreover, being such that interruption in the supplyof energy from the generating-station will have no action on the cut-outapparatus. The main feeders between the gen erating-stations andsubstations, and also, it may be, the auxiliary feeders between thesubstations, are provided, as usual, with excess-current cutouts atpoints near where they pass outward from the generating and substations.

Cut-out apparatus to operate in the manner described may convenientlycomprise a movable switch or cut-out device arranged in the main feederand controlled by an electro magnetic device comprising a series coil orcoils arranged in circuit with the main feeder, a shunt coil or coilsconnected across the main feeder and return lead near to the substation,a magnetic core or cores, and operating mechanism between the core orcores and the switch or cut-out device, the series and shunt coils beingso proportioned and arranged that the core or cores will not act to openthe feeder-circuit so long as current below, at, or above the normalamount is being supplied from the generating-station nor when the supplyof current is cut off, but will act to open the switch or cut-out in theevent of current being supplied in the reverse direction-viz., from thesubstation to the main feederas would be the case should a fault occurin such feeder between the generating and sub stations. I arrange thecoils and core or cores in such a way that a forward magnetic pull willbe exerted in one direction with a current supplied from thegeneratingstation and a backward magnetic pull with a current suppliedfrom the substation to the feeder to which the coils are connected, sothat nothing but an actual flow of current through the electromagneticdevice in the reverse direction to that required for supply purposeswill cause the switch or cut-out to be operated, so as to disconnect thefeeder from the substation. Consequently a fault in one feeder will notcause the cut-out or cut-outs of a healthy feeder which will then becalled upon to supply current to the substation normallysupplied by thefaulty feeder to open the circuit of such healthy feeder and interferewith the electric supply.

Apparatus to operate in the manner described can be constructed invarious forms. According to one construction such apparatus comprises amagnetic device having two distinct windings and one or more iron cores,one of the windings being connected in series with one of the feedersand the other connected as a shunt across the feeders, the movable coreor cores being mechanically connected to a catch device for releasing aweight or spring for operating the switch or cut-out device proper. Thetwo windings are so arranged relatively to each other that theircombined influence upon the iron core or cores tends to move it or themin one direction with a forward current and in the reverse directionwith a return-current. When the current in the feeders is flowing in itsnormal direction, the movement of the core or cores tends to securelylock the catch in position; but when the series current is reversedrelatively to the current in the shunt then the movement of the core orcores tends to release the catch and open the switch or cut-out.

Figure 1 of the accompanying drawings is a diagram showing ahigh-tension electrical distributing system comprising a centralgenerating-station connected to interconnected substations by feedersprovided with automatic cut-out apparatus according to this invention.Fig. 2 is a diagram illustrating a modified arrangement of an electricaldistributing system embodying myinvention. Figs. 3 and 4 are elevationsat right angles to each other, showing one construction of returncurrentcut-out suitable for carrying outmy invention; and Fig. 5 is a verticalsection of such apparatus on the line was of Figs. 3 and at. Fig. 6 is adetail view.

1, Fig. l, is a central generating-station connected by main feeders 2to transformersubstations 3, which are interconnected by auxiliaryfeeders or conductors 4, by means of which any one of the feeders 2connected to such interconnected substations can be temporarily out outof action for repair or other purpose without interrupting the supply ofelectricity to the substation to which it was directly connected, suchsubstation then receiving its supply of electricity through theauxiliary feeder 4, connecting it with another substation. 2 and t arethe returnleads of the main and auxiliary feeders, respectively. In analternating-current system the mains 2 2" and also mains t a are ofcourse each alternately positive and negative. 2 and t indicate ordinaryexcess-current cutouts, such as safety-f uses or magnetic or otherexcess-current cut-outs, arranged at the ends of the main and auxiliaryfeeders 2 and at, where they leave the central generating-station 1 andsubstations 3. Each substation in this case comprises one or moretransforming devices 3 for supplying electrical energy to local circuits3 3". In a continuous-current system of distribution the transformingdevices may be of the kind known as motortransformers, each consistingof a combined motor and dynamo. In an alternating-current system ofdistribution such as shown in Fig. 1 the said transforming devices maybe ordinary induction-transformers having primary and secondarywindings.

The automatic return-current cut-outs, arranged in connection with thefeeders 2 2 near to their points of connection with each substation, ashereinbefore described, are indicated diagrammatically at eachsubstation. Each of these cut-outs comprises a movable switch or contact5, that is provided with a weighted arm or lever 5, is adapted to engagewith fixed contacts 5 5 connected to the adjacent parts of the mainfeeder 2, and is controlled by an electromagnetic device comprising afield-magnet 5, made in the form of a bent iron core provided with aseries winding 5 and between the polar ends of which a rotaryarmature-core 5 provided with a shunt-winding 5 is so pivoted that thenormal position of its field is approximately at right angles to thefield produced by the series winding, the armature in this positionacting through a catch device 5", formed, in the example shown, by thefree end of the switch arm or lever 5, to normally hold the said arm orlever in the raised position and the switch 5 in the closed position.This position of the armature is insured, when no current is flowingthrough the cut-out device, by loading the armature 5 by means of aspring or weight, so that it normally bears against a fixed stop 5. Theseries winding 5 is arranged in series with the feeder 2. Theshuntwinding 5 may be connected as a shunt across the feeders 2 2, asshown in dotted lines, or across the distributing-mains 3 3, fed fromsuch feeders, as indicated in full lines. In the former case theshunt-winding may be connected to the secondary winding of atransformer, the primary winding of which is connected as a shunt acrossthe feeders 2 2. These different arrangements are electrically theequivalent of one another for the purpose required. As will be seen, thearrangement is such that when current is being supplied from thegenerating-station to the substations the direction of the currentsthrough the series and shunt windings of each cut-out device at a givenmoment will be represented by the arrow-heads (shown in full lines) andthe polarity of the field-magnet poles and armature-poles by the lettersN and S thereon, the relative direction of the currents in the shunt andseries windings being such as to tend to cause the armature to rotate ina clockwise direction against the stop 5 and so to securely lock theswitch 5 in the closed position, in which position it will obviously bealso maintained when no current is flowing through the main feeder andcutout device. If, however, either of the main feeders 2 should becomeshort-circuited, cur rent will be supplied to it from the correspondingsubstation in the direction of the generating-station and will fiowthrough the series Winding of the cut-out device in the oppositedirection or that shown by the dotted arrows, whereas the direction ofthe current in the shunt-winding will remain unchanged. As in this casethe direction of the series current relatively to that of theshunt-current will be reversed, the armature will rotate in a counterclockwise direction and release the weighted switch-lever 5, which willimmediately fall, and by opening the switch 5 disconnect the main faultyfeeder from the substation.

The induction of the shunt-circuit must be carefully adjusted to producethe requisite lag in phase of the shunt-current necessary to obtain thegreatest torque between the two magnetic fields at the time when thearmature is required to release the loaded switch.

Fig. 2 shows diagrammatically a low-tension system ofelectricaldistribution provided with return-current cut-outs according to thisinvention. In this case each pair of main feeders 2 2 from thegenerating-station 1 extends to one or more substations 3, from whichextend the distributing-mains or local circuits 3 3 which contain lampsor other translating devices 3 and which are connected direct to thefeeders 2 2 without the intervention of electric transformers. Some ofthe distributing-mains, such as those marked 3 3 may connect the mainfeeders 2 2 of different substations, and thus be available for use asauxiliary feeders, as and for the purpose hereinbefore described. Thereturn-current cutouts shown are like those hereinbefore described withreference to Fig. 1 and act in the same Way.

Figs. 3, 4, and 5 show one construction of return-current out out thatmay advantageously be used in carrying out my invention. In thisconstruction 6 is the movable switch or contact, consisting of achanneled piece of conductingmaterial-for example, bronze secured by abolt 7 to a porcelain or like insulator 8, having a corrugated exteriorand carried by a bar 9, that is made in two parts, so that the insulatorcan be clamped between their free ends. The other end of the bar 9 ispivoted to a bracket 10, extending from an iron base-plate 11, designedto be held in a vertical position against a wall or like support. Theends of the said movable contact-piece 6 are arranged to be each forcedbetween a pair of split metal spring-contacts 12 12, each pair beingcarried by a porcelain or like insulator 13, having a corrugatedexterior and a hollow base 13, that is fixed in a raised or channeledpart 11 of the base-plate 11 by lead, sulfur, or like cementingmaterial, the arrangementbeing such that when the fixed and movablecontacts 12 and 6 are properly engaged the pivoted bar 9 is vertical orapproximately so. At the outer side of the movable contact 6 is a weight14, carried by the curved arm 15 of a lever pivoted upon the same pin 16as the bar 9, carrying the movable contact 6, and the other arm 16 ofwhich is made short and so arranged that when the weight has beenreleased and has by falling acquired some momentum it will strikeagainst an abutment 9 on the bar 9 and rapidly disengage the movablecontact 6 from the fixed contacts 12. The weight 14 has secured to itsupper part a spring-catch 17, adapted to engage with a tooth or shoulder18 on a collar or disk 18, fixed to a horizontal spindle 19, that ismounted in brackets 20, extending from the upper part of the base-plate11, and has fixed to it the upper end of a trip-lever 21. At the lowerpart of the iron base-plate 11 is another raised or channel part 11", towhich is secured, by lead, sulfur, or like material, a corrugatedporcelain insulator 22, carryinga binding-screw 23 or equivalent forconnection to a return-main 2, Fig. 1. Centrally between the two raisedchaneled parts the baseplate is provided with a projecting part 11,having a curved surface and designed to serve as a pole-piece. In thespace between this pole-piece and the raised or chaneled parts 11 11 isarranged a series coil or winding 24, which may advantageously consistof a few turns of copper tape insulated from each other and designed tocarry the greatest current the apparatus will be called upon to carry.The inner end of this coil is fixed to a metal plate 25, carried by ametal rod 26, extending from a boss 27, which is provided with a metalsocket-piece 28, in which one end of the feeder 2, Fig. 1, iselectrically se-- cured and which is carried by another insulator 29,secured to the lower raised or channel part 11 of the base-plate 11. Theplate 25, rod 26, boss 27, and socket-piece 28 may consist of a bronzeor other metal casting. The other end of the series winding 24 issecured to a metal supporting-piece 29, connected to a plate 30,carrying onesay 12--of the pairs of fixed contacts 1212. The plate 30carrying the other pair of fixed contacts 12 is formed with asocket-piece 31-, in which is fixed one end of the adjoining length ofthe main feeder 2. 32 is the shunt-winding of fine wire wound upon anordinary shuttleshaped iron'core 33, mounted on knife-edge or otherbearings in lugs 11, projecting from the base-plate 11 and locatedwithin the series winding 24, one end of the shunt-winding being connected to the series winding, as at 24, and the other end to theinsulated terminal 23. Over the series and shunt windings 24 and 32,respectively, is or may be fixed an iron plate 34, having a pole-piece34, arranged opposite to the pole-piece 11 on the base-plate, so thatwhen the series winding is traversed by an electric current the ironplate will form, with the base-plate, a double magnetic circuit, whichis completed through the core 33 of the shunt-winding, which is arrangedbetween the polar projections 11 and 34. This core and shunt-winding 32are normally held in about the position shown in Fig. 4, so that thediametrical line jointing the poles of the core is at right angles ornearly so to the diametrical line joining the polar projectionsmagnetized by the series winding. The armature-core 33 may be held inthis position against a stop 35, carried, say, by the plate 25, by aweight or spring, hereinafter called a weight, preferably by making thelower polar side or end of the said armature-core 33 heavier than theother. To one of the plates 36 at the end of the armature-core is fixeda pin 37, that engages the lower bent end 21 of the trip-lever 21, so asnormally to hold the trip-lever 21 in a position to hold up the pivotedweight 1%. The point of contact between the said pin 37 and bent end 21of the lever is so arranged, as shown more clearly in Fig. 6, that it islo cated in an are A A, that passes through the longitudinal axis B ofthe armature and has its center at the axis 0, about which thetrip-lever 21 turns, and the said bent end of the lever is so shapedthat the pin can move over it in a direction to release itviz., in thedirection of the arrow, Fig. l-without having to move the said lever andconnected parts. By this construction the trip device is rendered verysensitive and reliable, as the only resistance which the coil and corewhen moved backward by a return-current have to overcome is that due tofriction between the pin and lever, which is small and may be renderedstill less by placing an antifrictionroller on the pin. Consequently asmall return-current will suflice to effect the automatic opening of theswitch or cut-out. The arrangement of the shunt-motor is such thatcurrent flowing in a forward direction through the series winding 2awill assist the armatureweight to hold the shunt-core 33 and winding 32in the position shown in Fig. 4-; but a return-current in the saidseries winding will overcome the armature-weight and turn the shunt coreand winding in the opposite direction sufficiently to disengage thetrip-pin 37 from the end 21" of the trip-lever 21 and release weightedlever 15 16, which in falling will strike against the abutment 9 andrapidly turn the movable contact into the open position, so as to effecta quick break in the feeder-circuit and prevent dangerous arcing.

In speaking of the direction of current I do not intend to excludealternate currents; but have described the invention for simpliciiy withdirect-current examples. I apply my invention in the case ofalternate-current working by making the apparatus according to theprinciples well understood, by which, although the currents arealternating, the simultaneous directions of the currents act relatively,as described with reference to di rect currents.

What I claim is 1. In an electrical distributing system, the combinationof a source of electrical energy, substations, feeders connecting saidsource with the said substations, an automaticallyopening return-currentcut-out at each station, means for normally holding the cut-out closed,and a motor controlling said holding means and having series windingslocated in the feeder-circuit and each motor adapted to release thecut-out-holding means only upon reversal of current in thefeeder-circuit when the same is traversed by a current from thesubstation, as set forth.

2. In an electrical distributing system, the combination with agenerating-station, substations fed therefrom, outgoing and returnfeeders connecting said generating-station with said substations,auxiliary feeders interconnecting said substations, and automaticreturn-current cut-outs each arranged in connection with the outgoingand return feeders near to their points of connection with thecorresponding substations, and each having a bias tending to open it, anelectric motor controlled by the feeder-current and adapted to actagainst the bias of the cut-out to keep it closed while current is beingsupplied to the substation and also when no current traverses thefeeder-circuit, and adapted to release the cut-ont and permit it to openonly upon a reversal of current in the feeder-circuit causing it to flowfrom the substation toward the generating-station, as set forth.

In a system of electrical distribution, the combination of agenerating-station, substations, main feeders connecting saidgenerating-station tosaid substations, auxiliary feeders interconnectingsaid substations, switches adapted to automatically open the mainfeedercircuits at points near to the substations, a detaining device forholding said switches closed, and electromagnetic devices arranged inthe feeder circuits and each adapted in response only to a reversal ofcurrent in the feeder to release the detaining device and permit theswitch to open, substantially as set forth.

4. In a system of electrical distribution, the combination of agenerating-station, substations, main feeders connecting saidgenerating-station to said substations, auxiliary feedersinterconnecting said substations, switches adapted to automatically openthe mainfeeder circuits at points near to the substations andshunt-motors for controlling said switches, each of said shunt-motorshaving its series winding in a main-feeder circuit and its shunt-winding across the said main feeder and its return-conductor, and a catchconnected with the motor for holding the correspondin g switch closedboth when traversed by current supplied to the corresponding station andwhen such current is cut off, and disengaged from said switch by themotor when the feedercircuit is traversed by a current supplied from thesubstation toward the generating-station, as set forth.

5. In an electrical distributing system, the combination with agenerating-station and substations connected thereto by feeders, of anelectromotive device having a wire-wound armature, an electromagneticfield therefor,

i E r one of said parts being in series in the feedercircuit, anautomatically-opening switch, a detaining mechanism for said switchconnected with said armature and whereby the switch is held closed untilthe armature is moved by a reversal of the current in the feeders,substantially as set forth.

6. In a system of electrical distribution, the combination of agenerating-station, substations, main and return feeders connecting saidsubstations to said generating-station, auxiliary feedersinterconnecting said substations, and return-current cut-out apparatuscontrolling each main feeder, each cut-out apparatus comprising a switchfor mechanically opening and closing the corresponding main-feedercircuit at a point near to the corresponding substation,a Weightadaptedwhen released to fall and strike the switch into its open position, atrip device adapted to hold the Weight in its raised and inoperativeposition, and a shunt-motor having a magnetic field excited by a seriesWindin g in the feedercircuit and a loaded movable armature-core that isexcited by a winding in a shunt between the feeder and itsreturn-conductor, and is adapted normally to hold the trip-lever in itsinoperative position, said series and shunt winding being so arrangedthat when current is being supplied from the generating-station to thecorresponding substation, and, also when current is cut off, thearmature-core will tend to rotate in a direction to hold the trip-leverin its inoperative position, and when current is supplied from thesubstation toward the generating-station, the armature-core will partlyrotate in the reverse direction and release the trip device and weight,substantially as described for the purposes specified.

7. In an electrical distributing system, the combination with agenerating-station and substation connected thereto by feeders, of amotor having a rotary wire-wound armature, an electromagnetic fieldtherefor, one of said parts being in series in the feeders, acircuitopening switch in the feeders having a weight tending to open thesame, and a detaining mechanism for said weight connected with thearmature and retained thereby until said armature is rotated uponreversal of current in the feeders substantially as set forth.

Signed at 2 Popes I-Iead Alley, Oornhill, in the city of London,England, this 28th day of February, 1898,

LEONARD ANDREYVS,

Witnesses:

WM. 0. BROWN, EDMUND S. SNEWIN.

